O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Siemens-Schuckert "Bulldog"
  Based on a pre-war design that had been constructed for Prince Friedrich Sigismund of Prussia, these two "Bulldog" monoplanes differed only in engine installation. They were completed early in 1915, but were declined by the authorities owing to their poor performance and handling qualities. Engine, 100 h.p. Siemens-Halske Sh I, 100 h.p. Mercedes D I.

J.Herris Siemens-Schuckert Aircraft of WWI (A Centennial Perspective on Great War Airplanes 12)

Pre-War & Early War SSW Aircraft

  The first SSW airplane was a biplane based on the Wright Flyer. Powered by a 50 hp Argus engine, it was built in 1909 and first flew on December 31, 1909. Damaged on landing after this flight, it was modified and flew again on March 9, 1910 carrying its designer, Bourcart, and one passenger. On March 11 it flew for a kilometer with three people aboard, but crashed when caught in a cross-wind. The next SSW design was a high-wing monoplane first flown in May 1911. A primitive design, it was not successful. A second monoplane to the Bleriot configuration was completed in September 1911, but its failure caused SSW to temporarily abandon aviation.


SSW "Bulldog"

  Shortly before the war Swedish designer Villehad Forssman, who had an office in Berlin, designed a monoplane known as the Bulldog for Prince Friedrich Sigismund of Prussia. Soon after the war started, Forssman offered SSW his design. The War Ministry desperately needed warplanes, and with their support SSW hired Forssman to supervise construction of two of his Bulldogs for reconnaissance. SSW began assembly of the aircraft at their Dynamo Works in their community of Siemensstadt.
  The first Bulldog, built in late 1914, was powered by a 100 hp Mercedes D.I in-line, six-cylinder engine. The second Bulldog, powered by one of the first 110 hp Siemens-Halske Sh.I counter-rotary engines, first flew on April 18, 1915. Both featured side-by-side seating for two crewmen. Both Bulldogs were rejected by the Army for mediocre flying qualities and poor performance. After modification, the rotary-powered Bulldog was used for air-launching trials for models of the missiles SSW was developing.